Vertebral compression fractures (“VCF”) represent a spinal injury and may result in prolonged disability. Generally, VCF involves the collapse of one or more vertebral bodies in the spine. VCF usually occurs in the lower vertebrae of the thoracic spine or the upper vertebrae of the lumbar spine. The anterior portion of the vertebral body is typically collapsed to a further extent than a posterior portion, resulting in a potentially wedge-shaped, compressed vertebral body, during a VCF event. VCF may result in deformation of the normal alignment or curvature, e.g., lordosis, of the vertebral bodies in the affected area of the spine. VCF and/or related spinal deformities may initiate from, for example, metastatic diseases of the spine, trauma and/or osteoporosis. Until recently, doctors were limited in their treatment options for VCF and related spinal deformities.
Minimally invasive surgical procedures for treating VCF have been developed. A cannula or other access tools are typically inserted through the posterior of the targeted vertebral body, usually through the pedicles in such procedures. For example, U.S. Published Patent Application No. 2009-0069850 describes a balloon with an implant mounted thereon that is insertable through a posterior duct into a compressed vertebral body and expanded to urge endplates of the vertebral body toward an original spacing or shape.
In another such procedure, generally referred to as vertebralplasty, a cannula or bone needle is passed through the soft tissue of the patient's back. Once positioned within the compressed vertebral body, a small amount of polymethylmethacrylate (PMMA) or other orthopedic bone cement is pushed through the needle into the targeted vertebral body. This technique may be effective in the reduction or elimination of fracture pain, prevention of further collapse, and a return to mobility in patients. However, this technique typically does not reposition the fractured bone into its original size and/or shape and, therefore, may not address the problem of spinal deformity due to the fracture.
Other treatments for VCF generally involve two phases including (1) reposition or restoration of the original height of the vertebral body and consequent lordotic correction of the spinal curvature; and (2) augmentation or addition of material to support or strengthen the fractured or collapsed vertebral body. This procedure is generally referred to as Kyphoplasty and is generally described in U.S. Pat. No. 6,241,734.
One such treatment involves inserting a catheter having a balloon mounted on a distal end into an interior volume of a fractured vertebral body, wherein the interior volume has a relatively soft cancellous bone surrounded by fractured cortical bone. The balloon is expanded within the interior volume in an attempt to restore the vertebral body towards its original height. The balloon is deflated and removed from the interior volume, leaving a void within the vertebral body. PMMA or other bone filler material is injected through the cannula into the void to stabilize the vertebral body. The cannula is then removed and the cement cures to augment, fill, or fix the size and general shape of the vertebral body.
Another approach for treating VCF involves inserting an expandable mesh balloon into the targeted vertebral body. The balloon remains inside the vertebral body after it is inflated with PMMA or an allograft product, which limits intra-operative loss of height of the repositioned endplates.
It is desirable to provide an improved system, method and instruments for minimally invasively inserting a containment device such as, for example, an implant or a balloon, into an interior volume of a patient's bone.